Culture and Ecology of Chaco Canyon and the San Juan Basin

The Classic Adaptation 205in and around Pueblo Bonito suggest the presence ofan increasingly larger central settlement (PuebloBonito, Chetro Ketl, Pueblo del Arroyo, and surroundingsites). Lekson (1984a, 1988a) attributed thisto a formalization of a regional network that includedother communities located throughout the San JuanBasin. Thus, the system would have reached its peakin the early A.D. l100s, and could have drawn onpeople living outside the canyon for seasonal labor.The McElmo Style. The change in masonrystyle and type of sandstone, as well as floor plan,attributed to the McEimo styie needed furtherevaluation. Judd (1927b) did not include the McElmostyle in his categories of masonry types, but Hawley(1938) did (her no. 8)(see Figure 6.2). GordonVivian and Mathews (1965) suggested the McElmostyle bega..~ around i\.D. 1050 and lasted throughA.D. 1124 or later, and was representative of aninflux of northern people into the canyon. Lekson(1984a) dated Judd's types III and IV and Hawley'stypes 6, 7, and 9 to the period from A.D. 1050 to1115. All are considered the products of skilledmasons. Lekson (1984a:267-268) concluded that themasonry style and ground plan of the structures, plusthe use of carbon-painted ceramics, correlate best withtime, rather than the migration of northerners into thecanyon. Not only are multi storied structures withround rooms enclosed within the room block early inChaco Canyon, but the ground plan is not typical inthe Mesa Verde area. When found in the north, it isoften thought to come from the south. The use ofdifferent sandstones in construction is attributed to theavailability of the resource in specific areas of thecanyon. The McElmo masonry style found in thecentral canyon at Kin Kletso, Casa Chiquita, and NewAlto probably represents the exhaustion of the darkbrownsandstone outcrops in this area, whereas theBonito style at Wijiji farther east persists because thisoutcrop had not been exhausted by earlier great houseconstruction in this area.The function of the McElmo units was evaluated(Lekson 1984a). The size, shape, and placement ofrooms in the Bonito and McElmo room blocks aremore important than the differences in building materialand masonry style. Suites and room blocksslowly evolve from a set of paired small rooms behindlarge rectangular rooms (similar to those at contemporarysmall house sites, but larger) to linear suitessurrounded by many almost-square small rooms of asimilar size. Lekson and Judge (1978) proposed thatthese sites may have been used primarily for storage,with only a few people in residence as a caretakerpopUlation; yet even an unusually large crop of comcould have been stored in two back rooms at ChetroKetl.Overall, the form and function of rooms(determined by size and features) at great housesindicate both stability and change through time.Rectangular rear rooms tend to be featureless andaverage 12 m 2 in size. They are thought to representa storage function (Lekson 1984a:41-42) and are anexample of stability through time. They are frontedby much larger rooms (Windes's [1987] big-roomsuites) during the A.D. WOOs. By A.D. 1060, theearlier paired room suites (two smaller rooms frontedby one or two larger rooms) begin to be replaced by aset of linear rooms, with room size decreasing fromfront to back (Lekson 1984a:62). Between A.D. 900and 1100, the average size of front rooms decreasedfrom 45 m 2 to 10 m 2 •More recent investigators have used space syntaxanalysis to confirm a trend toward increased specializationin both small sites and great houses aroundA.D. 1050. Not only are there differences in the useofspace within small sites, but by A.D. 1100 it is alsoapparent between small sites (Bustard 1996, 1999).Bustard (1995, 1999) and Cooper (1995, 1997)document similar changes in great houses; e.g., thelack of household patterning, and increased spatialsegregation. Cooper (1995) also noted differencesbetween Aztec West and Salmon (both in the north, orSan Juan River, area) vs. Chaco Canyon great houses.However, neither could determine the exact functionof the great houses.Unusual Features. Unusual architectural featuresthat occur, often at two or more great house sitesbut not in all, include masonry piers, buttressing,filled rooms, use of natural features, ramadas andportals, balconies, stairs, and room-wide platforms(Table 6.8). Some features may be time-related. Theappearance of ramadas and portals is common in theearly great house sites; e.g., at Pueblo Bonito (Room3, Judd 1964:95; Pepper 1920:7). The use of masonrypiers as roof supports in great kivas (e.g., Room308 in Pueblo Bonito [Judd 1964:96], rooms 117 and